Over the past 12 months, as optimism collided with reality, Mr. Bush increasingly found himself uneasy with General Casey’s strategy. And now, as the image of Saddam Hussein at the gallows recedes, Mr. Bush seems all but certain not only to reverse the strategy that General Casey championed, but also to accelerate the general’s departure from Iraq, according to senior military officials.

General Casey repeatedly argued that his plan offered the best prospect for reducing the perception that the United States remained an occupier — and it was a path he thought matched Mr. Bush’s wishes. Earlier in the year, it had.

But as Baghdad spun further out of control, some of the president’s advisers now say, Mr. Bush grew concerned that General Casey, among others, had become more fixated on withdrawal than victory.

Now, having ousted Mr. Rumsfeld, Mr. Bush sees a chance to bring in a new commander as he announces a new strategy, senior military officials say. General Casey was scheduled to shift out of Iraq in the summer. But now it appears that it may happen in February or March.

By mid-September, Mr. Bush was disappointed with the results in Iraq and signed off on a complete review of Iraq strategy — a review centered in Washington, not in Baghdad. Whatever form the new strategy takes, it seems almost certain to include a “surge” in forces, something that General Casey insisted earlier this year he did not need and which might even be counterproductive.

In a telephone interview on Friday, General Casey continued to caution against a lengthy expansion in the American military role. “The longer we in the U.S. forces continue to bear the main burden of Iraq’s security, it lengthens the time that the government of Iraq has to take the hard decisions about reconciliation and dealing with the militias,” he said. “And the other thing is that they can continue to blame us for all of Iraq’s problems, which are at base their problems.”

Yet if Mr. Bush does send in more American forces, historians may well ask why it took him so long. Some Bush officials argue that the administration erred by refusing to send in a bigger force in 2003, or by sufficiently bolstering it when the insurgency began to take hold.

If Casey retires in early February, and still opposes this plan, the hearings will be devestating.

Bush's main problem is a simple one: who is he backing? It is clear that Sadr now runs the government. All this talk of shoving him aside was Green Zone nonsense. One word from Sistani, and that was done.

The Mahdi Army is now, in effect, the government's main force. The uniformed units have only a nominal loyalty to the government

The Iraqis never delivered four of the six Iraqi Army battalions that they had committed to the effort. Some of the Iraqi police units proved to be so infiltrated by Shiite militias that they had to be pulled off duty for retraining.Weaknesses in the Iraqi Forces

In the Sunni stronghold of Dora, in southwestern Baghdad, American troops were forced to clear thousands of homes twice: the Iraqi security forces who moved in behind them were too few, and too little dedicated to the task, to keep the insurgents from returning.

In neighborhoods like Baya, the Shiite-dominated Iraqi National Police set up menacing checkpoints on the routes Sunnis used to seek medical attention or buy fuel.

“They were trying to dominate the Sunni population and terrorize them to the point that they would leave Baghdad or leave the neighborhood,” recalled Lt. Col. James Danna, who had led the Second Battalion, Sixth Infantry Regiment, which oversaw those areas. He said that like the first Baghdad security operation, the second also failed. As the American elections approached, White House officials say, they believed it would amount to political suicide to announce a broad reassessment of Iraq strategy. But they recognized that unless they began such a review, they would be forced to accept the conclusions of the final report of the Iraq Study Group — headed by James A. Baker III, the former Republican secretary of state, and Lee H. Hamilton, the former Democratic congressman.

The effort started in September, around the time Mr. Bush decided to oust Mr. Rumsfeld. In the days before the election, Mr. Bush suggested during an interview that Mr. Rumsfeld could stay until the end of his term — a deliberately misleading statement that Mr. Bush said later was necessitated by the political season. Similarly, it was days after the election that the White House revealed that a major Iraq review was under way.

In public, Mr. Bush continues to insist that he and Mr. Maliki share the same vision. In private, one of his former aides said, “he questions whether Maliki has the will or the power” to make good on any commitments.

American military officers have also wondered if the Shiite-dominated Iraqi government and the Americans share the same vision. Were the Iraqis not pulling their weight because they did not have the capability to provide security and proceed with reconstruction? Or did the Iraqi authorities have a sectarian agenda?

It is only a matter of time before an Iraqi Army unit turns on the US forces. The US has no options, but it pretends it does.